Protecting device for steam-turbine blades



H. C. JOHNSON AND'J E H. PERCY. PROTECTING DEVICE FOR STEYAM'TURBINE BLADES.

' APPLICATION FILED MAY 29. 1917. RENEWED DEC. 24, 1919.

1,333,661. Patented Mar. 16,1920.

UNITE STATES PATENT-OFFICE.

HANS c. JOHNSON AND EDWIN H. PERCY, or FORT BRAGG, CALIFORNIA.

Application m May 29, 1917, Serial No; firm.

1 To all whom it may concern:

' Be it 'known that we, HANs C. JOHNSON and EDWIN H. PERCY, citizens of the United States;- and residents of Fort Bragg, in the county of Mendocino and State of California, have invented a certain new and useful Improvement in Protecting Devices for Steam Turbine Blades. of which the follow ino" is a specification.-

; protecting means for the blades at the low pressure end of the bladed cylinder, our. objectbeing-the provision of a protecting device capable of effective and eflicient use without detracting from the power and efliinvolving a considerable loss of time and expense as well as great annoyance;

In carrylng out our invention'we provide means capable of ready installation in *con- I nection with a turbine cylinder at thelow pressure end thereof, the action of whlch'in use is to throw ofi any backed up water and continually force the same. away from the adjacent cylinder bladesand out of contact therewith, at the same time providin for substantially unrestricted passage 0 the r steam to the exhaust so as to avoid interference. with the Ordinary functions of the'turbine or decrease of its normal efliciency.

In the accompanying drawings illustrating our invention:

Figure 1 is a sectional view through a p0r- 7 tion of a steam turbine of the type to which our invention is applied, illustrating the relative position of the protecting means provided thereby;

Fig. 2 is an end view of the turbine c linder provided with our improvements, 00king at the low pressure end thereof;

Fig. 3 is a side view. of a portion of the low pressure end of the cylinder with our .ur present'invention relates generally to steam' turbines, and more particularly PROTECTING nEvIOE EOE swan-TURBINE EL'ADEs.

Specification of Letters Patent. N Patented Mar. 16,

Renewed DeceinberM, 1 919. Seria1 NO.'347,1 99.

and 1 Fig, 4 is a diagram illustrating the relainvention partly biokenawayand in section,

tive engagement'of the stationary and" movingblades and protecting member provided by our invention.

Referring now to these figures, and more particularly to Fig, 1, the turbine cylinder is seen generally at 10, 'the'fast moving blades I 11-of which, adjacent its low pressure end, are normally subject to the actionof water backed up in the exhaust 12, and unpro- 1 tected as against contact therewith.

Our invention contemplates theconnection of means to the low pressure'end of the cylinder 10, which will protect the fast moving blades 11 and obviate their contact with water backed up in the exhaust 12, and to this end provides a circular plate 13, the inner hub portion 14 of which is solid to a point adjacent and slightly beyond the periphery of the cylinder 10,- and is bolted by annular bolts 15 to the low pressure end of said cylinder, as particularly seen by reference to: Figs. 2 and 3, the relation of this blade 18 with the surrounding members of the turbine being plainly seen from Fig. 1.

The plate 18 has an annular series of ra- 'iially slotted openings 16 cut therethrough at an angle of substantially forty-five d'e-' grees-and falling away angularly toward the moving blades 11 in the direction of move- 1 ment of the latter, as plainly seen by reference to 4, in which the blades 11 appear in their operative position between series of stationary bladesv 17, the annular edge of the plate 13 being left with the arm 18 sufliciently heavy to protect and support the webs '19 between slots 16.

Thus, falling away as they do toward the moving blades at the angle stated and in the direction of rotative movement of the blades of the cylinder 10, the annular series of slots steam to the exhaust, and the webs between these slots provide for an elfective and efficient discharge of any backed up or accumulated water away from the blades 11, so as to obviate contact of the blades therewith and consequent injury of the blades for the 16 provide for'unrestri'cted passage of the secured to and moving with the low pressure end of the cylinder, having an annular series of lnclined slots ad acent the low pressure'cylinder blades, the webs between which and rotating therewith, said plate having an I annular series of radially disposed slots inclined With respect to the axis of the cylinder, and; inclined Webs between which, slots act to normally force the accumulated water away from the cylinders.

,3. In a turbine, the combination with the turbine cylinder, of a protecting plate 5"- curedto the low pressure endlof the cylinder to rotate therewith, said plate having an inner hub portion bolted to the adjacent cylinder end and having an outer solid rim, and.

an annular series of radially extending slots between 1ts head and run portions, extending through the plate at angles inclined With respect to th axis of the cylinder, for the pur pose described,

4:. In a turbine, the combination with the rotating turbine cylinder, of means adjacent the, low pressure end thereof arranged to provide for unrestricted passage of steam to the exhaust and at the same time prevent contact of the turbine bladeswith the Water backed up in the exhaust, at the adjacent end of the cylinder. I v 1 Ina turbine, the combination with the rotating turbinecylinder, ofineans adjacent, the low pressure end thereof arranged to provide for unrestricted. passage of steam to-the exhaust and at the same time prevent contact of the turbine blades With the Water backed up in the exhaust, at the adjacent end of the cylinder, said nieansbeing connected to; and rotating vith'the said-cyL V inderQ Hans JOHNSON. EDWINI-I. PERCY. 

